Here are a couple of more things you can do to save you some money on your electric bill. Install new filters twice a year, for window units hand wash and dry filter monthly. Hire a energy efficiency company to seal and insulate attic ducts. Install ceiling fans to make your house feel cooler. If your central unit is more than 10 years old upgrade it will pay for itself in the long run. Thanks for looking at my blog and check past post for more helpful tips.